OBJECTIVE: 1. Expose larval instar crickets to LD-cycles, LL and DD and determine at what point instar circadian control of locomotion becomes evident. 2. Investigate the role of the corpora allata for the sexual responsiveness of the female as expressed in locomotor activity and phonotactic behavior. 3. Trace the axonal pathways of ordinary neurons from the pars interverebralis by application of the cobalt-sulfid filling technique. BIBLIOGRAPHIC REFERENCE: Rence, B. and W. Loher: Arrhythmically singing crickets: Thermoperiodic reentrainment after bilobectomy. Science, 190:385-387 (1975).